Dental impression trays are widely used to take teeth impressions and form casts from the impressions. Dental impression trays form a concavity or interior in which soft impression material is placed. The impression tray and impression material are then introduced into a patient's mouth. An impression is made by the dentist positioning the impression tray and impression material over the patient's teeth and applying pressure so that the impression material disperses around the teeth and dental arch.
The dental impression tray and impression material are removed from the patient's mouth after the impression is made. The next step in the process is to pour plaster or other casting material into the impression and into the interior of the dental impression tray.
Lower dental impression trays typically define a lingual recess to accommodate a patient's tongue during the taking of an impression and it is not uncommon for the plaster or other casting material to flow over the tray and into the lingual recess, resulting in an unsightly appearance and improper lingual representation. It is desirable when taking orthodontic impressions that the final model be smooth and accurate.